Enhanced liquid pressure cycle having an ejector

ABSTRACT

The enhanced liquid pressure cycle having an ejector consists of a high-pressure positive displacement liquid rotary pump (liquid pressure pump). The liquid pressure pump provides the primary high-pressure mass flow to the evaporator and the pressure mass flow to the driving force input to a condensing and mixing ejector. The system is further enhanced by a vapor compressor/turbine/motor combination which provides the ability to suck out and lower the refrigerant pressure output from the evaporator while the interconnected turbine offsets the power input requirements of the vapor compressor. The high-pressure liquid from the liquid pressure pump is divided into two pressure streams. The first stream is directed to an expansion valve then on to an evaporator for space air or other medium cooling. The second stream is directed to the driving force input port of an ejector. This high-pressure input mixes with the low-pressure output from the turbine. The result of this mixing provides for sufficient pressure enhancement to condense the combination liquid and vapor refrigerant as it passes through the condenser. The liquid flow from the condenser proceeds back to the liquid pressure pump and the cycle is repeated. The horsepower to pressurize a liquid for a given mass flow of refrigerant for the enhanced liquid pressure cycle is significantly less than the horsepower required for a vapor compression cycle of equal mass flow.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigeration system, which utilizesa positive displacement rotary liquid pump for its primary high-pressurerefrigerant generation and is further enhanced with a vaporcompressor/turbine/motor combination along with corresponding expansionvalve, evaporator, ejector and condenser.

2. Description of the Prior Art

The vapor compression refrigeration cycle is the leading cooling methodfor millions of residential and commercial installations. The vaporcompression cycle utilizes a vapor compressor to increase a low-pressurerefrigerant gas to a high-pressure Refrigerant gas. The high-pressuregas then passes through an air or water-cooled condenser where the gaschanges state into a high-pressure liquid upon the removal of heat fromthe high-pressure gas. This high-pressure liquid then passes through anexpansion valve into an evaporator. During this expansion process, heatis absorbed in the evaporator with space air or other medium beingcirculated through the evaporator. The net result is the cooling of theconditioned space or medium.

The vapor compression cycle has only been improved on the margins.Typical improvements include more efficient vapor compressor designs,larger condenser and evaporator coils, use of variable speed modulation,use of liquid centrifugal pumps for increased expansion valve efficiencyand the use of ejectors to reduce the amount of work expended by a vaporcompressor. The goal of the enhanced liquid pressure cycle is toovercome the limited on the margin improvements of the vapor compressioncycle.

SUMMARY

The enhanced liquid pressure cycle having an ejector consists of ahigh-pressure positive displacement liquid rotary pump (liquid pressurepump). The liquid pressure pump provides the primary high-pressure massflow to the evaporator and the pressure mass flow to the driving forceinput to a condensing and mixing ejector. The system is further enhancedby a vapor compressor/turbine/motor combination which provides theability to suck out and lower the refrigerant pressure output from theevaporator while the interconnected turbine offsets the power inputrequirements of the vapor compressor.

The high-pressure liquid from the liquid pressure pump is divided intotwo pressure streams. The first stream is directed to an expansion valvethen on to an evaporator for space air or other medium cooling. Thesecond stream is directed to the driving force input port of an ejector.This high-pressure input mixes with the low-pressure gas output from theturbine. The result of this mixing provides for sufficient pressureenhancement to condense the combination liquid and vapor refrigerant asit passes through the condenser. The liquid flow from the condenserproceeds back to the liquid pressure pump and the cycle is repeated.

The horsepower to pressurize a liquid for a given mass flow ofrefrigerant for the enhanced liquid pressure cycle is significantly lessthan the horsepower required for a vapor compression cycle of equal massflow.

It is an object of the invention to provide a simple refrigerationsystem with significant advantages over systems of prior art.

Additional objects and advantages of the invention are set forth, inpart in the description which follows, and in part, will be obvious fromdescription or may learned by practice of the invention. The objects andadvantages of the invention will be realized in detail by means of theinstrumentalities and combinations particularly pointed out in theappended claim.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing is incorporated in and form a part of thespecification and together with the descriptions serves to explain theprinciples of the invention in which FIG. 1 is a schematic diagram ofthe enhanced liquid pressure cycle having an ejector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is understood that both the foregoing general description andfollowing detailed description are exemplary and explanatory only, andare not restrictive of the invention as claimed. The accompanyingdrawing which is incorporated herein for reference, and constitute partof the specifications, illustrate certain embodiments of the invention,and together with the detailed description serve to explain theprinciples of the present invention.

Reference will now be made in detail to the embodiment of therefrigeration system of the present invention. This example isillustrative only and should not be construed to limit the inventionunnecessarily.

As shown in FIG. 1, the refrigeration cycle of the present inventionbegins with increasing the pressure of a liquid refrigerant HFC-134Awith a high-pressure liquid pressure pump 10 powered by a fixed orvariable speed motor 11.

This high-pressure liquid travels through conduit 12 and enters theexpansion valve 14 then into evaporator 15. The expansion valve 14 opensand closes depending upon the set point temperature requirements of theevaporator 15. There are several schemes to accomplish this controlfunction currently in use today. During this expansion process, heat isabsorbed in the evaporator 15 with space air or other medium beingcirculated through the evaporator 15.

The low-pressure gas output of the evaporator 15 proceeds throughconduit 16 to compressor 17. The compressor 17 provides a reliable meansof sucking and lowering the pressure in evaporator 15 and compresses thelow pressure gas into a high-pressure gas.

The high-pressure gas proceeds through conduit 18 to the turbine 19where it is expanded into a low-pressure gas. During this expansion thehorsepower generated by the turbine 19 offsets or reduces the horsepowerinput required for compressor 17. It is to be noted that the electricalmotor 20, compressor 17 and turbine 19 are interconnected on a commondrive shaft 21. This allows the electrical motor 20 to provide the basichorsepower input to the compressor 17 which is significantly offset bythe horsepower output of the turbine 19. The expanded low-pressure gasoutput of the turbine 19 proceeds through conduit 22 into thelow-pressure port 23 b of the ejector 23. Concurrently approximatelyfifty to seventy five percent of the high-pressure flow from the liquidpressure pump 10 proceeds through conduit 12 and 13 to the driving forceinput port 23 a of the ejector 23. This high-pressure liquid input mixeswith the low-pressure gas output from the turbine 19 whereby thecombined pressure is sufficient to condense the refrigerant output ofcondenser 25. The pressure enhancement capabilities of a typical ejectoris more fully described in an early U.S. Pat. No. 3,277,660 and mostrecently refined in U.S. Pat. No. 6,438,993. Upon leaving ejector 23,the refrigerant flow proceeds through conduit 24 and enters condenser 25where heat is removed from the refrigerant with a cooling media beingcirculated through condenser 25 thereby condensing into a liquid. Uponleaving condenser 25, the liquid refrigerant then proceeds throughconduit 26 to a liquid receiver 27 then through conduit 28 to the liquidpressure pump 10 where the cycle is repeated.

It will be apparent to those skilled in the art that variousmodifications can be made in the construction and configuration of thepresent invention without departing from the scope or spirit of theinvention. For example, the embodiment mentioned above is illustrativeand explanatory only. Various changes can be made in material as well asthe configuration of the device to engineer the specific desiredoutcome. Thus it is intended that the present invention cover themodifications and variations of the invention, provided they come withinthe scope of the appended claims and their equivalents.

1. An enhanced liquid pressure cycle having an ejector comprising: apositive displacement rotary liquid pump for the systems primary highpressure generation; an expansion valve disposed at the inlet side ofthe evaporator; an evaporator for evaporating low-pressure refrigerantthereby absorbing heat after being decompressed by an expansion valve;an ejector for mixing the high-pressure stream and a low-pressure streamwhose combined output pressure is sufficient for the operatingconditions of the condenser; a condenser for cooling and condensing intoa liquid the refrigerant discharged by the ejector; acompressor/turbine/motor combination which operates as a single unitinterconnected with a common drive shaft whereby the compressorcomponent sucks out and lowers the pressure in the evaporator. Thecompressor high-pressure output is inputted into the turbine componentwhere the high-pressure gas is expanded generating an offsettinghorsepower required by the compressor. The third component, the electricmotor, provides the basic starting horsepower and makes up for anyoffsetting horsepower deficiency between the compressor and turbine; aliquid receiver to insure that sufficient liquid refrigerant isavailable for the liquid pressure pump.
 2. An enhanced liquid pressurecycle having an ejector according to claim 1 wherein the mixingrefrigerant is HFC-404A;
 3. An enhanced liquid pressure cycle having anejector according to claim 1 wherein the mixing refrigerant is HFC-407A;4. An enhanced liquid pressure cycle having an ejector according toclaim 1 wherein the mixing refrigerant is HFC-410A.